Use ternary operator in freemarker?

Question

I just want to do something like this:

Answer 1

You can define a custom function if that is declared like so:

<#function if cond then else="">
  <#if cond>
    <#return then>
  <#else>
    <#return else>
  

The function can be used in any ${...} expression. Your code would look like so:

In contrast to @kapep, I think you should use a function, not a macro. Macros produce (textual) output, while functions return a value that can for example be assigned to a variable, but also written to the output, so using a function is more flexible. Furthermore, the way to apply the function is much closer to using a ternary operator, which would also be used inside ${...} expressions, not as a directive.

For example, if you need the conditional link target multiple times, it would make sense to assign it to a local variable:

<#assign targetUrl=if(a, 'a.htm', 'b.htm')/>
link 1
...
link 2

Using the function instead of the macro, @kapep's examples would look like this:

${if(someBoolean, "someBoolean is true")}  


${if(someBoolean||otherBoolean, "hello,"+user.name, 1+2+3)} 




<#list seq as x>
    ${if(x_index==0, "first", "not first")}
<#list>